Method and apparatus for detecting loose ends and missing filters in cigarettes

ABSTRACT

A METHOD AND APPARATUS FOR DETECTING IRREGULAR SURFACES OF ARTICLES AND PARTICULARLY LOOSE ENDS AND MISSING FILTERS IN CIGARETTES PROVIDES FOR THE IMPINGEMENT OF AN AIR STREAM AGAINST AT LEAST ONE END OF EACH CIGARETTE. IF THE TOBACCO FILLER AT THE END OF THE CIGARETTE IS LOOSE OR PITTED OR IF THE FILTER PLUG IS MISSING RESULTING IN A CAVITY AT THE END OF THE CIGARETTE, AN AIR TURBULENCE IS CREATED BY THE AIR STREAM RESULTING IN A DISTINCTIVE SOUND WHICH CAN BE DETECTED BY A TRANSDUCER AND UTILIZED TO REJECT DEFECTIVE CIGARETTES.   D R A W I N G

March 13, 1973 s. HARRISON, JR 3,720,311

METHOD AND APPARATUS FOR DETECTING LOOSE ENDS AND MISSING FILTERS IN CIGARETTES Filed Jan. 26, 1971 2 Sheets-Sheet 1 'mvemuz EDMUND HnRmsnN Jn- ATTORNEYS March 13, 1973 E. HARRISON, JR I 3,720,311 METHOD AND APPARATUS FOR DETECTING LOOSE ENDS AND MISSING FILTERS IN CIGARETTES Filed Jan. 26, 1971 v 2 Sheets-Sheet 2 c Q I I06 [Db FIGS 9 TESTING STATION r 29 EJECTDR Lc 1 r T INVENTDZ EDMUND HRRRiSDNAP.

A-rroraueYs United States Patent 1 3,720,311 METHOD AND APPARATUS FOR DETECTING LOOSE ENDS AND MISSING FILTERS IN CIGARETTES Edmund Harrison, Jr., Richmond, Va., assignor to Molins Machine Company, Inc., Richmond, Va. Filed Jan. 26, 1971, Ser. No. 109,859 Int. Cl. B07c /34; G01b 5/28 U.S. Cl. 20979 61 Claims ABSTRACT OF THE DISCLOSURE This invention is concerned with an improved method and apparatus for detecting irregular or rough surfaces on articles and more particularly for detecting and rejecting cigarettes having loose ends and/ or missing filters.

Though the present invention is useful in detecting rough or irregular surfaces on various types of articles the invention will be described in the context of its application to cigarettes. In the manufacture of cigarettes a continuous strip of paper is wrapped about loose tobacco filler, the edges of the paper being sealed together to form a continuous rod. The rod is then severed into cigarette lengths and optionally a mouthpiece portion such as a filter plug is attached at one end. Means are provided in the continuous rod-making apparatus for obtaining a rod in which the tobacco filler adequately fills the interior of the wrapper. However, despite precautions taken periodically cavities containing little or no tobacco filler are formed in the continuous rod resulting in cigarettes, the ends of which contain loose tobacco filler or are pitted. Such cigarettes are said to have loose ends and are considered defective and must be removed from the cigarette production line. Also during production occasionally a filter plug will be missing from a cigarette leaving a hollow cavity at one end thereof. Such cigarettes having defective filters must also be removed from the production line.

Various mechanisms are known in the prior art for automatically detecting loose or pitted ends in cigarettes or missing filters on the ends of cigarettes. One commonly known mechanism involves the use of mechanical feelers as, for example, are disclosed in U.S. Pat. Nos. 2,284,117 and 3,116,478. With such an arrangement the feelers must be reciprocated to and away from the ends of each successive cigarette as it is conveyed through a testing area. For such mechanisms to operate, a considerable amount of time is required and thus the conveyor system for transporting cigarettes through the testing area must either be stopped momentarily while the feeler mechanism is operated to move the feeler into contact with the end of the cigarette and then return the feeler to its original position, or a plurality of the mechanisms must be supported on or adjacent the conveyor system to move with the cigarettes during at least a part of their travel during which time contact is made by the "Ice 2 feelers. Such arrangements have not been satisfactory particularly with more recent models of cigarette-making machines in which the cigarette production rate has doubled to about 4,000 per minute.

More recently another method and apparatus for testing cigarettes for loosely packed ends and missing filter plugs was devised in which compressed air is blown axially towards an end of the cigarette and the back pressure created by a defective cigarette having a loose or pitted end or a missing filter is measured. If the back pressure is greater than a predetermined amount the cigarette is defective and is rejected. Such devices are disclosed in U.S. Pat. Nos. 3,484,970 and 3,485,357. However, they are not entirely satisfactory particularly with a highspeed cigarette-making machine. One of the major problems with such devices is that the distance between the end of the nozzle through which the air is projected and the ends of the continuous stream of cigarettes passing the nozzle must be maintained exactly constant as any variations in this distance caused by irregularities in the positioning of cigarettes longitudinally on the conveyor past the nozzle will result in a change in the measured back pressure even though the cigarettes are not defective in any way. As a result, good cigarettes are rejected by the testing apparatus.

It is an object of the invention to accurately detect rough or irregular surfaces on articles.

Another object of the invention is to accurately detect and measure the degree of roughness or irregularity on the surfaces of articles.

A further object of the invention is to accurately detect rough or irregular surfaces on a succession of articles and direct the articles along dilferent paths depending on the results of the testing.

Another object of the invention is to test the ends of cigarettes to accurately detect loose or pitted ends or missing filter plugs.

A further object of the invention is to accurately test the ends of a succession of cigarettes and to provide means to generate a signal indicating a defective cigarette which signal is utilized to reject the defective cigarette.

A still further object of the invention is to test the ends of a succession of cigarettes to accurately detect loose or pitted ends or missing filter plugs at a substantially higher rate than had previously been possible.

Another object of the invention is to provide an apparatus for testing the ends of a succession of cigarettes whereby cigarettes which are found to be defective may be immediately rejected without interfering with the operation of the testing apparatus.

A still further object of the invention is to provide means for determining the degree of looseness or pitting in the ends of each cigarette of a stream of cigarettes and regulate rejection apparatus such that only cigarettes having looseness or pitting above a predetermined degree will be rejected.

In accordance with the present invention a method and apparatus have been devised for detecting and measuring the degree of irregularity of a surface of an article such as the ends of cigarettes even when the cigarettes are being transported at the rate of up to 9,000 cigarettes per minute. More particularly, in accordance with the present invention an air stream is impinged against the end of a cigarette whereby in the case of a loose or pitted end or in the case of a cavity resulting from a missing filter, irregularities in the air stream are created producting tur bulence in the air stream and a distinctive sound, the intensity of which is proportional to the condition of the end of the cigarette. Transducer means such as a microphone is provided for detecting the intensity of any sound produced and further means is provided for measuring the intensity of the sound and for producing a signal to 3 actuate a reject mechanism or a memory device in the event that the intensity is greater than a predetermined level.

The testing device in accordance with the present invention will now be described by way of example with reference to the accompanying drawings in which:

FIG. 1 shows a side view of testing apparatus and a conveyor for transporting cigarettes;

FIG. 2 is an elevational view taken along the line 2-2 of FIG. 1;

FIG. 3 is a front view of the testing apparatus taken along the line 3-3 of FIG. 2;

FIG. 4 is a sectional view of the testing apparatus taken along the line 4-4 of FIG. 3;

FIG. 5 shows a modification of the testing apparatus of FIGS. 1 and 2;

FIG. 6 is a sectional view taken along the line 66 of FIG. 5;

FIG. 7 shows diagrammatically a memory device for recording the location of defective cigarettes and actuating a rejecting device; and

FIG. 8 is an electrical circuit diagram of the testing apparatus.

Referring to FIGS. 1, 2, 3 and 4, cigarettes C to be tested are delivered by a fluted belt conveyor 1 passing around pulley 27 into flutes 2 of a rotating drum 3 mounted on a rotatably driven shaft 4. The peripheral flutes 2 are arranged lengthwise of the drum, each for receiving a single cigarette which cigarettes are held in place in the flutes by suction drawn through holes in the flutes which communicate with a suction chamber in the interior of the drum 3. A detailed description of the construction of the drum and the means 28 for controlling the suction is found in U.S. Pat. No. 3,266,295 to Williamson. The cigarettes C are transported in the flutes along a circular path past a testing station shown generally at 5. A housing 6 includes a nozzle 7 which is a flattened end of a tube 8 located in the bore of a tubular channel 9, the end of which is axially aligned with each cigarette C as it passes through the testing station 5. The tube 8 is connected by bore 10 and nipple 11 to a source of compressed air (not shown). The tubular channel 9 communicates through the larger bore 12 with a microphone or electroacoustic transducer 13 located in recess 14 of housing 6 and which converts sound transmitted through the tubular channel 9 and bore 12 to an electrical signal transmitted through circuit 15. To avoid the transmission of mechanical vibrations directly to the microphone 13, annular thermoplastic rings 16 are positioned around the microphone to insulate it.

Adjacent the downstream side of the testing station 5, considering the direction of the movement of the cigarettes C, is an arrangement shown generally at 17 for rejecting unsatisfactory cigarettes. An air nozzle 18 is connected through conduit '19 and valve 20 to an air pump (not shown) by which, when the Valve is opened, air is blown in a short blast through the nozzle 18. The valve 20 is operated by a solenoid 21 as will be described subsequently. A short blast of air from the nozzle 18 serves to blow unsatisfactory cigarettes lengthwise off the drum 3.

Cigarettes which have not been found to be unsatisfactory are carried up by the drum 3 and transferred into flutes 22 of a further suction drum 23, which deposits them on a conveyor 24. The suction in the flutes 2 of drum 3 is cut ofl in each flute as the flute 2 becomes contiguous to a flute 22 on drum 23 to permit transfer of cigarettes between the two drums. The mechanism 28 for accomplishing this is described in greater detail in the above mentioned US. Pat. No. 3,266,295.

FIG. 8 shows a circuit diagram extending between the microphone 13 and the solenoid of the ejector '17. The electrical signal from the microphone 13 is transmitted through circuit 15 and coupling transformer to amplifier A where it is suitably amplified. The feedback arr g me t with Iit0rs R and R2 e e m es the g of the amplifier. The relative values of resistors R and R in the case of cigarette testing may be such as to give a signal increased by a factor of 40. The output from amplifier A is then transmitted to amplifier A where it is inverted but not increased, since the values of resistors R and R are equal. The inversion is desirable since signals of only one polarity can be applied to a discriminator, shown generally at 26, and it is desirable to utilize both the positive and negative portions of the signal. By inverting the signal and taking outputs from both amplifier A and A through diodes D and D both the negative and positive portions of the original signal will appear as positive signals which in this instance is forty times greater than the output of the transformer 25.

With respect to the discriminator 26, transistor T will only pass signals greater than the bias applied from variable resistor R which, as will be explained later, is the means for predetermining the sound level and thus signal level at which rejection of faulty cigarettes will occur. In other words, the variable resistor R serves to generate a reference against which the amplified signal is compared.

Signals from transistor T are applied to switching transistor T In the absence of a signal, the transistor T remains in conducting condition. However, with the input of a signal from transistor T it opposes the current in resistor R and the signal from the switching transistor T is transmitted to the solenoid '21 through a suitable driving circuit 29 causing valve 20 of the ejector mechanism 17 to be opened to emit the short blast of air required to eject an unsatisfactory cigarette from the drum 3. Alternatively, the signal from the switching transistor T may be applied to a memory device to be described later.

The dimensions of the nozzle 7 are not critical and will vary depending upon the material being tested as well as upon variations in the construction and operation of the testing apparatus itself. It has been found that for testing cigarettes the tube 8 may have an inside diameter of about & inch which is flattened to form the nozzle 7 which has a discharge opening approximately 0.140 x 0.015 inch. With respect to the tubular channel 9, the dimension is also not critical. However, it has been found in the case of testing cigarettes that it should have about the same internal diameter as the outside diameter of the cigarettes being tested. Cigarettes generally have an outside diameter ranging between 6.5 and 9 mm. The discharge opening of the nozzle 7 is preferably located approximately 3 mm. inwardly of the end of the outer tubular channel 9.

The air pressure applied to the nozzle 7 and the velocity of the air passing through the nozzle 7 are not critical and will vary depending upon the material being tested as well as the specifications of the testing apparatus itself. The minimum air pressure and flow for satisfactory operation in the case of testing cigarettes is approximately 50 mm. Hg pressure and 1500 cc./min. respectively. There is no is no maximum pressure or velocity; however, the pressure should preferably not be gerater than about mm. Hg nor the flow greater than 4000 cc./ min.

The sound intensity generated by the air stream imping ing against the end of a defective cigarette is essentially directly proportional to the air pressure, and it therefore is important that the air pressure remains constant. This can be assured by incoroprating a conventional air pressure regulator in the air supply fed to the testing apparatus.

The distance between the end of the outer tubular channel 9 and the end of the cigarette passing through the testing station 5 is not critical. The preferred distance range will depend to some extent on the air pressure and velocity being used. As an example, with the air pressure at about 50 mm. Hg and the flow about 1.5 liters/min. it was found that there was no significant variation in output of diodes D and D when the distance between the opening of the channel 9 and the end of a cigarette having a loose end varied beween 0.10 and 0.23 inch. A reasonable amount of variation in the distance between the opening of the channel 9 and the ends of the succession of cigarettes is possible without affecting the sensitivity of the testing device.

The air stream projected from the nozzle 7, preferably in a direction parallel to the axis of the cigarette being tested and perpendicular to the surface being tested, impinges on the end of each cigarette C as the cigarette passes through the testing station 5. A desirable cigarette having a smooth end causes an orderly dispersion of the air stream generally in a 360 plane at 90 to the axis of the cigarette. On the other hand, a loose or pitted end of a cigarette or a cavity resulting from a missing filter causes irregularities in the dispersion of the air stream after striking the end of the defective cigarette producing turbulence and a distinctive sound. The nature and degree of disturbance and resulting sound is directly related to the size and depth of the pits or cavities in the area upon which the air stream impinges and the intensity of the generated sound is characteristically related to the degree of pitting or the existence of a cavity in the cigarette. Thus, it is possible to regulate the detecting apparatus whereby only cigarettes having pitting above a predetermined depth and thus generating a predetermined sound intensity will be ejected by the ejector mechanism 17.

The sound frequencies generated by the air turbulence caused by a loose end or a missing filter may range between 20 and 1000 hertz, but the predominant frequencies containing the highest energy levels are from about 250 to 500 hertz. It has also been found that the intensity of the sound produced is nearly four times greater for a missing filter compared to that for a loose end.

Any type of electro-acoustic transducer may be used to detect the sonic vibrations, a convenient transducer being a dynamic microphone such as that produced by the Radio Corporation of America, Model HK 100, wherein the output level at 1000 Hz. and sound pressure of 1 dyne/square cm. is 57 dBv. The output impedance is 50,000 ohms.

FIGS. 5 and 6 show a testing apparatus similar to that shown in FIGS. 1-4 and those elements of the apparatus which are substantially identical both in FIGS. 1-4 and in FIGS. 5 and 6 are identified with the same numerical designation. The detecting apparatus shown in FIGS. 5 and 6 is designed to test both ends of the same cigarette simultaneously as it is transported through the testing station on drum 3. The detecting. apparatus includes two separate housings 106 mounted in spaced relationship on a support member 130. Each of the housings 106 includes an air nozzle 7 and a tubular channel 9 which are so positioned at the testing station that the ends of each cigarette C as it passes through the testing station on drum 3 confront the respective nozzle and tubular channel. A further housing 131 is also mounted on the support member 130 between the two housings 106. The housing 131 contains a chamber 132 in which is mounted the microphone 13 with the annular insulators 16. The chamber 132 communicates through two ports 133 and 134 with large conduits 135 and 136 which are connected to the larger bores 12 in each of the housings 106. Any sound generated at either or both ends of a cigarette is transmitted through the respective bores 12, large conduits 135 and 136 and ports 133 and 134 to the chamber 132 where the sound is received by the microphone 13. A duct system 138 also contained in the housing 131 conducts compressed air through nipple 139 on the housing 131 to smaller conduits 140 and 141 which in turn conduct the compressed air to the respective smaller bores and nozzles 7 in each of the housings 106.

With the detector arrangement shown in FIGS. 5 and 6, it is possible to test both ends of a cigarette C simultaneously using a common source of compressed air and a common microphone. The microphone is connected to the circuitry as shown in FIG. 8 which serves to regulate the ejector mechanism 17 Alternatively, both ends of a cigarette may be tested simultaneously using two separate systems as shown in FIGS. 1-4. With such an arrangement two electrical systems similar to that shown in FIG. 8 will be required though they both may serve to control a single ejector mechanism 17.

Since the cigarettes pass through the testing station 5 at a relatively high rate, the location of the rejecting mechanism must be adjusted such that it will reject only the defective cigarettes. The ejecting mechanism is positioned such that the defective cigarette passes between the testing station and the ejecting mechanism in the period of time that passes between the instant the sound is detected at the testing station and the ejecting pulse of air is emitted. If it is undesirable to eject the defective cigarette a relatively short period of time following its detection, a memory device such as that shown in FIG. 7 and described in considerable detail in US. Pat. No. 3,435,443 to Muir may be used. With this arrangement, the signals transmitted from switching transistor T are fed into a recording head which magnetizes a selected one of a plurality of discerte magnetizable elements 141 supported about the periphery of a non-magnetizable carrier member 142 which is rotatably mounted on brackets 143 supported on base 144. Each of the elements 141 represents a cigarette on the conveyor mechanism shown in FIGS. 1 and 2. The carrier member 142 is synchronized to rotate at a speed dependent upon the speed of the conveyor mechanism so that when a magnetized element reaches the reading head 9 the corresponding cigarette on the conveyor mechanism will be adjacent the ejector mechanism 17, and the signal transmitted by the reading head 9 will actuate the rejecting mechanism 17 causing the cigarette to be ejected from the conveyor mechanism. The memory device shown in FIG. 7 permits ejection of cigarettes either from the drum 3 or from a subsequent conveyor such as the conveyor belt 24.

Other forms of memory devices such as that shown in FIG. 7 of the above mentioned US. Pat. No. 3,266,295 may be used. Furthermore, other forms of ejector mechanisms may be used such as the more complex arrangement using a rejector drum shown in FIG. 5 of US. Pat. No. 3,266,295. Alternatively, the testing device of the present invention may be used in conjunction with the arrangement for testing the wrappers of the cigarette rods as described in US. Pat. No. 3,266,295. With this arrangement both the wrappers and the ends of the cigarette may be tested on the same fluted drum.

It will be appreciated that with the testing device of the present invention no moving elements such as feelers are required. Furthermore, there is no need for a critical adjustment of the air stream pressure or geometry. Detection is accomplished by non-contacting means allowing ejection at the point of detection as shown in FIG. 5 The detector itself is self-cleaning and the components used are relatively simple and inexpensive. At the same time, the device offers the ability to detect defective cigarettes while being conveyed at a substantially greater rate than has previously been possible with prior art detection devices.

As many embodiments may be made of the above invention, and as changes may be made in the embodiments set forth above, without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative only and not in a limiting sense.

I claim:

1. A method for determining the condition of a surface comprising:

(a) impinging an air stream against said surface with sufiicient velocity to cause the deflected air stream to generate a characteristic sound if said surface is irregular, and

(b) detecting any sound produced by the air stream deflected from said surface.

2. A method for determining the condition of an end of a cigarette comprising:

(a) impinging an air stream against said cigarette end with sufficient velocity to generate a characteristic sound if said cigarette is irregular, and

(b) detecting any sound produced by the air stream impinging against said cigarette end.

3. A method for measuring the degree of irregularity of a surface of an article comprising:

(a) impinging an air stream against said surface wi.h sufficient velocity to cause the deflected air stream to generate a characteristic sound, and

(b) detecting and measuring the intensity of said sound produced by the air stream deflected from said surface.

4. A method for measuring the degree of irregularity of an end of a cigarette comprising:

(a) impinging an air stream against said cigarette end with sufficient velocity to generate a characteristic sound, and

(b) detecting and measuring the intensity of said sound produced by the air stream impinging against said cigarette end.

5. A method for identifying among a plurality of articles a defective article characterized by a surface having at least a predetermined minimum degree of irregularity comprising:

(a) impinging an air stream against the surface of each article in succession with sufficient velocity to cause the deflected air stream to generate a characteristic sound when any of said surfaces are irregular, and

(b) detecting said sound produced by the air stream deflected from the surface of an irregular article.

6. A method for identifying a defective article characterized by a surface having a predetermined minimum degree of irregularity comprising:

(a) impinging an air stream against the surface of the article with sufficient velocity to generate a characteristic sound when a surface is irregular,

(b) detecting and measuring the intensity of said sound produced by the air stream impinging against an irregular surface, and

(c) comparing said intensity measurement against a predetermined standard for the minimum degree of irregularity.

7. A method for detecting a loose or pitted end in or a missing filter on a cigarette comprising:

(a) impinging an air stream against at least one end of the cigarette with sufficient velocity to generate a characteristic sound if the end is loose or pitted or a filter is missing, and

(b) detecting any sound produced by the air stream impinging against the end of the cigarette.

8. A method for detecting any loose or pitted ends in a plurality of cigarettes or any missing filters on a plurality of cigarettes comprising:

(a) successively impinging an air stream against at least one end of each cigarette with sufficient velocity to generate a characteristic sound when an end is loose or pitted or a filter is missing, and

(b) detecting any sound produced by the air stream impinging against ends of the cigarettes.

9. A method as defined in claim 8 further comprising:

(a) measuring the intensity of said sound and (b) comparing said intensity measurement against a predetermined standard for differentiating between an acceptable cigarette end and a loose or pitted end or an end with a missing filter.

10. A method as defined in claim 8 wherein said cigarettes are fed continuously transversely to their lengths past a testing station and said air stream is impinged against at least one end of each cigarette as it passes said testing station.

11. A method for eliminating any article having an unacceptable degree of irregularity in a surface thereof from a plurality of articles, comprising: i

(a) continuously feeding said articles in succession,

(b) impinging an air stream against said surface of each article with sufiicient velocity to generate a characteristic sound when dispersed by an irregular surface,

(0) detecting and measuring the intensity of any sound produced by the air stream impinging against said surface, and

(d) removing from said plurality of articles any articles having an irregular surface producing a sound intensity above a predetermined level.

12. A method as defined in claim 11 comprising the further step of comparing said measured intensity with a predetermined standard, any articles having an irregular surface producing a sound intensity greater than said standard being removed from said plurality of articles.

13. A method as defined in claim 11 for eliminating any cigarette having an unacceptably loose or pitted end or a missing filter from a plurality of cigarettes wherein said cigarettes are continuously fed in succession in a direction transversely to their lengths and said air stream is impinged against at least one end of each cigarette.

14. Apparatus for determining the condition of a surface of an article comprising:

(a) means for impinging an air stream against said surface with sulficient velocity to cause the deflected air stream to generate a characteristic sound when said surface is irregular, and

(b) means for detecting any sound produced by the air stream deflected from said surface.

15. Apparatus for determining the condition of a surface of an article comprising:

(a) means for impinging an air stream against said surface With sutficientvelocity to generate a characteristic sound when said surface is irregular,

(b) means for detecting any sound produced by the air stream impinging against said surface, and

(c) means for measuring the intensity of said sound produced by said air stream as it is dispersed by said irregular surface,

(d) whereby the degree of the irregularity of said surface may be determined.

16. Apparatus as defined in claim 15 for detecting a loose or pitted end in or a missing filter on a cigarette.

17. Apparatus for determining the condition of a surface of an article, comprising (a) nozzle means for impinging an air stream against said surface with sufficient velocity to generate a sound when said surface is irregular; and

(b) detecting means for detecting any sound produced, said detecting means comprising a microphone and a tubular member surrounding said nozzle and communicating with said microphone for transmitting sound thereto.

18. Apparatus for detecting unacceptable loose or pitted ends in or missing filters on cigarettes comprising:

(a) means for feeding a plurality of said cigarettes in a direction transversely to their lengths,

(b) means for producing and impinging an air stream against at least one end of each cigarette with suflicient velocity to generate a characteristic sound as said air stream is dispersed by a loose or pitted end or a missing filter, and

(c) means for detecting and measuring the intensity of any sound produced by said air stream as it is dispersed by the loose or pitted end or the missing filter,

(d) whereby the degree of intensity of said sound inglicates the degree of looseness or pitting or a missing ter.

19. Apparatus for separating articles having at least a predetermined minimum degree of irregularity in a surface thereof from articles having a surface with less than said predetermined minimum degree of irregularity comprising (a) means for feeding said plurality of articles,

(b) means for impinging an air stream against said surface of each article with sufiicient velocity to generate a characteristic sound when said air stream is dispersed by an irregular surface,

(c) means for detecting and measuring the intensity of said sound produced by said air stream as it is dispersed by said irregular surface and for producing a signal when said sound intensity is at least at a predetermined level corresponding to said predetermined minimum degree of irregularity, and

(d) means responsive to said signal for separating those articles having surfaces which cause at least said predetermined level of sound intensity from those articles having surfaces which cause less than said predetermined level of sound intensity.

20. Apparatus eliminating cigarettes having unacceptable loose or pitted ends or missing filters from a plurality of cigarettes comprising:

(a) means for feeding said plurality of said cigarettes in a direction transversely to their lengths,

(b) means for impinging an air stream against at least one end of each cigarette with suflicient velocity to {generate a characteristic sound when said air stream is dispersed by a loose or pitted end or a missing filter,

(c) means for detecting and measuring the intensity of said sound produced by said air stream as it is dispersed by the loose or pitted end or by the missing filter and for producing a signal when said sound intensity is greater than a predetermined level, and

(d) means responsive to said signal for ejecting from said plurality of cigarettes any cigarettes causing said signal to be produced.

21. Apparatus as defined in claim 20 wherein said means for detecting and measuring sound intensity and for producing a signal comprises:

(a) means for sensing said sound and generating a corresponding electrical signal,

(b) means for amplifying said electrical signal, and

(c) discriminator means for comparing said amplified signal against a predetermined standard and for transmitting a signal to said ejecting means,

(d) whereby a sound intensity greater than said predetermined maximum which is caused by a cigarette having an unacceptably loose or pitted end or a missing filter will actuate said ejecting means.

22. Apparatus as defined in claim 21 wherein said amplifying means comprises:

(a) a first amplifier means to increase the electrical signal from said sensing means, and

(b) a second amplifier means for inverting the amplified signal from said first amplifier means,

(c) whereby signals of only one polarity are supplied to said discriminator means.

23. Apparatus as defined in claim 21 wherein said discriminator means comprises:

(a) a discriminator transistor and (b) bias means applied to said discriminator transistor,

(c) whereby said discriminator transistor will only pass signals greater than the bias to said ejecting means.

24. Apparatus as defined in claim 20 wherein said ejecting means comprises a memory device for recording signals from said discriminator and for causing said ejecting means to be actuated.

25. A method as defined in claim 2 wherein the velocity of said air stream impinged against said cigarette end is between about 1500 and 4000 cc./min.

26. A method as defined in claim 4 wherein the velocity of said air stream impinged against said cigarette end is between about 1500 and 4000 cc./ min.

27. A method as defined in claim 7 wherein the velocity of said air stream impinged against said cigarette end is between about 15 00 and 4000 cc./min.

28. A method as defined in claim 8 wherein the velocity of said air stream impinged against said cigarette end is between about 1500 and 4000 cc./min.

29. A method as defined in claim 13 wherein the velocity of said air stream impinged against said cigarette end is between about 1500 and 4000 cc./min.

30. Apparatus as defined in claim 16 wherein the velocity of said air stream impinged against said cigarette end is between about 1500 and 4000 cc./min.

31. Apparatus as defined in claim 18 wherein the velocity of said air stream impinged against said cigarette end is between about 1500 and 4000 cc./ min.

32. Apparatus as defined in claim 20 wherein the velocity of said air stream impinged against said cigarette end is between about 1500 and 4000 cc./min.

33. A method of testing the firmness of the end portion of a cigarette, comprising directing a stream of air towards the end portion of the cigarette with sufiicient velocity so as to generate a characteristic sound if the end is soft, and detecting any sound produced by the air impinging against the cigarette.

34. A method according to claim 33 in which the stream is directed against the tobacco end face of the cigarette.

35. A method according to claim 33 wherein the velocity of said air stream impinged against said cigarette end portion is between about 1500 and 4000 cc./min.

36. Apparatus for testing the firmness of the end portion of a cigarette, comprising nozzle means to direct a stream of air towards the end portion of the cigarette with sufiicient velocity so as to generate a characteristic sound if the end is soft, and means to detect any sound produced by the air impinging against the cigarette.

37. Apparatus according to claim 36 in which a microphone is used to detect any sound produced.

38. Apparatus according to claim 36 in which the nozzle means is arranged to direct the stream of air against the tobacco end face of the cigarette.

39. Apparatus according to claim 36 wherein the velocity of said air stream impinged against said cigarette end portion is between about 1500 and 4000 cc./min.

40. Apparatus for testing cigarettes for loose ends, comprising means for carrying each cigarette in turn past a testing station; means for directing a stream of air towards an end portion of each cigarette; a microphone; ejector means for ejecting cigarettes with loose ends; and control means for operating the ejector means responsive to the microphone producing a signal indicative of a loose end.

41. Apparatus according to claim 40 wherein the velocity of said air stream impinged against said cigarette end portion is between about 1500 and 4000 cc./min.

42. Apparatus for testing the firmness of an article comprising:

(a) means for impinging a stream of air against a surface of the article,

(b) a chamber having one wall formed at least partly by a microphone,

(c) means defining an inlet to the chamber, and

(d) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end adjacent to the article in a position where the conduit inlet receives a stream of air which is reflected from the article when the firmness of the article is below a predetermined level, thus producing a pressure pulse in the chamber which is sensed by the microphone.

43. Apparatus for testing the firmness of an article comprising:

(a) a testing station,

(b) means for moving the article through the testing station,

(c) means at the testing station for impinging a stream of air against a surface of the article,

(d) a chamber having one wall formed at least partly by a microphone,

(e) means defining an inlet to the chamber, and

(f) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end at the testing station in a position where the conduit inlet receives a stream of air which is reflected from the article when the firmness of the article is below a predetermined level, thus producing a pressure pulse in the chamber which is sensed by the microphone.

44. Apparatus for testing the firmness of a part of each of a succession of articles comprising:

(a) a testing station,

(b) means for moving the articles successively through the testing station,

() means at the testing station for impinging a stream of air against the surface of the part of each article to be tested,

(d) a chamber having one wall formed at least partly by a microphone,

(e) means defining an inlet to the chamber, and

(f) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end at the testing station in a position where the conduit inlet receives a stream of air which is reflected from the article when the firmness of the article is below a predetermined level, thus producing a pressure pulse in the chamber which is sensed by the microphone.

45. A method as defined in claim 2 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end is between about 20 and 1000 hertz.

46. A method as defined in claim 4 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end is between about 20 and 1000 hertz.

47. A method as defined in claim 7 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end is between about 20 and 1000 hertz.

48. A method as defined in claim 8 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end is between about 20 and 1000 hertz.

49. A method as defined in claim 13 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end is between about 20 and 1000 hertz.

50. Apparatus as defined in claim 16 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end is between about 20 and 1000 hertz.

51. Apparatus as defined in claim 18 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end is between about 20 and 1000 hertz.

52. Apparatus as defined in claim 20 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end is between about 20 and 1000 hertz.

53. A method as defined in claim 33 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end portion is between about 20 and 1000 hertz.

54. Apparatus according to claim 36 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end portion is between about 20 and 1000 hertz.

55. Apparatus according to claim 40 wherein the frequency of said sound generated by the impingement of said air stream against said cigarette end portion is between about 20 and 1000 hertz.

56. Apparatus for testing the firmness of an article comprising:

(a) means for impinging a stream of air against a surface of the article,

(b) a chamber having one wall formed at least partly by a microphone,

(c) means defining an inlet to the chamber, and

(d) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end positioned adjacent to the article such that, when the firmness of the article is below a predetermined level, said microphone will be caused to generate an electrical signal.

57. Apparatus for testing the firmness of an article comprising:

(a) a testing station,

(b) means for moving the article through the testing station,

(0) means at the testing station for impinging a stream of air against a surface of the article,

((1) a chamber having one wall formed at least partly by a microphone,

(e) means defining an inlet to the chamber, and

(f) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end at the testing station in a position such that, when the firmness of the article is below a predetermined level, said microphone will be caused to generate an electrical signal.

58. Apparatus for testing the firmness of a part of each of a succession of articles comprising:

(a) a testing station,

(b) means for moving the articles successively through the testing station,

(c) means at the testing station for impinging a stream of air against the surface of the part of each article to be tested,

(d) a chamber having one wall formed at least partly by a microphone,

(e) means defining an inlet to the chamber, and

(f) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end at the testing station in a position such that, when the firmness of any one of said articles is below a predetermined level, said microphone will be caused to generate an electrical signal.

59. Apparatus for testing a cigarette containing tobacco filler comprising:

(a) means for impinging a stream of air against said cigarette.

(b) a chamber having one wall formed at least partly by a microphone,

(0) means defining an inlet to the chamber, and

(d) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end positioned adjacent to the cigarette such that, when the tobacco filler in said cigarette is loose, said microphone will be caused to generate an electrical signal.

60. Apparatus for testing a cigarette containing tobacco filler comprising:

(a) a testing station,

(b) means for moving the cigarette through the testing station,

(c) means at the testing station for impinging a stream of air against said cigarette,

(d) a chamber having one wall formed at least partly by a microphone,

(e) means defining an inlet to the chamber, and

(f) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end at the testing station in a position such that, when the tobacco filler in said cigarette is loose, said microphone will be caused to generate an electrical signal.

61. Apparatus for testing a part of each of a succession of cigarettes containing tobacco filler comprising:

(a) a testing station,

13 14 (b) means for moving the cigarettes successively References Cited through I116 testing station, UNITED STATES PATENTS (0) means at the testing station for impinging a stream of air against the part of each cigarette to be tested, 3650145 3/1972 l 73-37 (cl) a chamber having one wall formed at least partly 5 3564902 2/1971 Hmtmann 7337 3,600,612 8/1971 Beeken 340-15 by a mlcwPhoPe 2,751,577 6/1956 DuBois 340-15 (e) means defining an inlet to the chamber; and 3,223,194 12/1965 Michael 181 5 LD (f) a conduit having an outlet end joined to the inlet to the chamber, and an inlet end at the testing station ALLEN N KNOWLES, Primary Examiner in a position such that, when the tobacco filler in any 10 one of said cigarettes is loose, said microphone will US. Cl. X.R. be caused '10 generate an electrical signal. 209 2 1 119; 73 7 6 105 9; 340 15; 5 R 

